Titanium alloy for making a golf club head

ABSTRACT

A titanium alloy for making a golf club head includes aluminum in an amount of greater than 8.0 wt % and not more than 10.0 wt %, molybdenum in an amount of greater than 0 wt % and not more than 2 wt %, vanadium in an amount of greater than 0 wt % and not more than 2 wt %, silicon in an amount of greater than 0 wt % and not more than 2 wt %, and a balance of titanium, based on a total weight of the alloy. A golf club head made by the titanium alloy is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of the U.S. patentapplication Ser. No. 11/759,861, filed on Jun. 7, 2007, and the entirecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a titanium alloy, more particularly to atitanium alloy for making a golf club head.

2. Description of the Related Art

Ti-6A1-4V titanium alloy is a conventional alloy for making a golf clubhead that is popular in the market because the golf club head madethereby has satisfactory mechanical strength and abrasive resistancemeeting the requirements of most golf players.

Ti-6A1-1Mo-1V-2Zr titanium alloy is another convention alloy for makinga golf club head having superior mechanical strength and abrasiveresistance. The alloy primarily includes 6 wt % aluminum (A1), 1.0 wt %molybdenum (Mo), 1.0 wt % vanadium (V), 2.0 wt % zirconium (Zr), and abalance of titanium (Ti).

Although the aforesaid conventional titanium alloys may be used formaking a golf club head having high mechanical strength and abrasiveresistance, it is still desirable in the art to provide a titanium alloyusable to make a golf club head having relatively light weight atrelatively low production cost while having superior mechanical strengthand abrasive resistance.

U.S. Pat. No. 2,918,367 discloses a titanium based alloy composedessentially of 2% to 8% of aluminum, 2% to 6% of a metal selected fromthe class consisting of vanadium, molybdenum and mixtures thereof, 0.1%to 1.5% of silicon, and balance of titanium. As indicated, the amount ofaluminum in this patent may range from a minimum effective amount forappreciably increasing the strength, of about 2% of the alloy, to amaximum amount of aluminum, of about 8% of the alloy. A preferred rangeis about 4% to about 6% aluminum in the alloy. Even narrower ranges forthe amount of aluminum are preferred in the case of certain specificuses.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a titaniumalloy which may be used for making a golf club head having relativelylow density, relatively low production cost, and superior mechanicalstrength and abrasive resistance.

Another object of the present invention is to provide a golf club headmade of the titanium alloy.

Accordingly, in a first aspect of the present invention, a titaniumalloy for making a golf club head includes:

aluminum in an amount of greater than 8.0 wt % and not more than 10.0 wt%;

molybdenum in an amount of greater than 0 wt % and not more than 2 wt %;

vanadium in an amount of greater than 0 wt % and not more than 2 wt %;

silicon in an amount of greater than 0 wt % and not more than 2 wt %;and

a balance of titanium, based on a total weight of the alloy.

In a second aspect of the present invention, a golf club head is made ofthe titanium alloy.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As described above, the amount of aluminum in the titanium alloy of thepresent invention is greater than 8.0 wt % and not more than 10.0 wt %,which is higher than that of aluminum used in the conventional Ti-6Al-4Vand Ti-6Al-1Mo-1V-2Zr titanium alloys and the alloy disclosed in U.S.Pat. No. 2,918,367. An increase in aluminum reduces the density of thetitanium alloy of the present invention. Therefore, a golf club headmade of the titanium alloy of the present invention may have arelatively light weight compared to the golf club heads made of theaforesaid conventional titanium alloys. Furthermore, an increase inaluminum raises extensibility of the titanium alloy of the presentinvention. Therefore, the titanium alloy of the present invention may beprocessed easier to make a golf club head. Noted that the amount ofaluminum in the titanium alloy of the present invention should not behigher than 10.0 wt %. If the amount of aluminum is higher than 10.0 wt%, the flowability of the alloy may be further reduced so that moresilicon must be used to improve the flowability. As such, the amount oftitanium in the titanium alloy must be significantly reduced, and themechanical strength of the golf club head may therefore decrease.Furthermore, since the over growth of crystals in the alloy may beinhibited by aluminum, the crystal grains of the alloy may be maintainedat a relatively fine size, which may improve the mechanical strength andabrasive resistance of the golf club head made of the alloy of thepresent invention.

Molybdenum in an amount of greater than 0 wt % and not more than 2 wt %may further increase the high temperature strength, the creep strength,and the high temperature hardness of the alloy so as to improve theabrasive resistance and the mechanical strength of the golf club headmade of the alloy of the present invention.

Vanadium in an amount of greater than 0 wt % and not more than 2 wt %may also avoid the over growth of crystal grains in the alloy so as tomicronize the crystal grains of the alloy, thereby improving themechanical strength and abrasive resistance of the golf club head madeof the alloy of the present invention.

The increased amount of aluminum in the alloy of the present inventionmay reduce the flowability of the alloy during the fabrication of a golfclub head from the alloy. Silicon is added to increase the flowabilityof the alloy and to improve the processability thereof. The processingof the alloy may therefore be made easier and the production cost maytherefore be reduced.

The golf club head can be made of the alloy of the present inventionusing a conventional method for fabricating a golf club head thatincludes a former processing stage and a latter processing stage. Theformer processing stage involves precision casting technology, andgenerally includes the steps of mold-making, wax injection, hanging,dipping, dewaxing, casting, cutting, heat treating, etc. The latterprocessing stage includes the steps of surface grinding, washing,lacquering, punching, embedding, assembling, torque testing, polishing,etc.

EXAMPLES

Alloys having compositions listed in the following Table 1 was made.Golf club heads were fabricated from the alloys, and were compared tothe golf club heads made of the Ti-6Al-4V titanium alloy and theTi-6Al-1Mo-1V-2Zr titanium alloy in terms of tensile strength, yieldstrength, extensibility, density, and total weight. The results areshown in Table 2.

TABLE 1 Al Mo V Si Ti Examples (wt %) (wt %) (wt %) (wt %) (wt %) Ex. 18.1 1.0 1.0 1.0 88.9 Ex. 2 8.3 1.0 1.0 1.0 88.7 Ex. 3 8.5 1.0 1.0 1.088.5 Ex. 4 9.0 1.0 1.0 1.0 88.0 Ex. 5 10.0 1.0 1.0 1.0 87.0

TABLE 2 Tensile Yield Extensi- Total strength strength bility Densityweight (Mpa) (Mpa) (%) (g/cm³) (g) Ex. 1 882 820 12 4.29 147.29 Ex. 2885 822 12 4.29 147.29 Ex. 3 889 825 11 4.28 146.95 Ex. 4 805 770 104.28 146.95 Ex. 5 850 722 12 4.27 146.61 Ti—6Al—4V 820 738 6 4.51 150titanium alloy Ti—6Al—1Mo—1V— 816 799 7.5 4.45 148 2Zr titanium alloyTi—8Al—1Mo—1V— 880 818 8 4.2-4.3 148.25 1Si titanium alloy

As shown in the results of Table 2, in the golf club head made of thealloy of the present invention, the tensile strength and the yieldstrength are improved or comparable, the extendibility is significantlyraised, and the density and total weight are reduced as compared to thegolf club heads made of the Ti-6Al-4V titanium alloy, theTi-6Al-1Mo-1V-2Zr titanium alloy, and the Ti-8Al-1Mo-1V-1Si titaniumalloy. Therefore, the titanium alloy of the present invention may beused for making a golf club head having relatively light weight andsuperior mechanical strength and abrasive resistance.

While the present invention has been described in connection with whatare considered the most practical and preferred embodiments, it isunderstood that this invention is not limited to the disclosedembodiments but is intended to cover various arrangements includedwithin the spirit and scope of the broadest interpretation so as toencompass all such modifications and equivalent arrangements.

1. A titanium alloy for making a golf club head, comprising: aluminum inan amount of greater than 8.0 wt % and not more than 10.0 wt %;molybdenum in an amount of greater than 0 wt % and not more than 2 wt %;vanadium in an amount of greater than 0 wt % and not more than 2 wt %;silicon in an amount of greater than 0 wt % and not more than 2 wt %;and a balance of titanium, based on a total weight of said alloy.
 2. Agolf club head made of the titanium alloy of claim 1.